No-Cooling Tower for full credit? Option 2 - Optimize Water Use for Cooling - 100% Reduction

It is my understanding that the v4.1 WEc Optimize Process Water Use, Opt 2. Optimize Water Use for Cooling will require the project to include a cooling tower if all three points are pursued. 

If no cooling tower, then the ACP is still available.

You are correct, Grace.

The April 2021 edition of the BD+C v4.1 reference guide states:

"if the above conditions* are met and the project team eliminates the need for cooling towers or evaporative condensers in the proposed building design, then the project team may document a 100% reduction in water use for cooling"

*Above conditions refers to the project's baseline system including a cooling tower or evaporative condenser.

Thanks for the post, I just learned some more LEED!

:)

hallo Grace and Dave,  I am following the discussions above but still i didn`t get it. Do we get the full 3 points or not? I have the same situation as Grace mentioned in the first post. 

Thank you :)

projects registered after April 21, 2023 are no longer able to use previous editions of the v4.1 reference guide language. 

https://www.usgbc.org/articles/starting-april-21-new-guidelines-leed-v41...

The 'No Cooling Tower' pilot credit was an Alternative Compliance Path to the v4 credit, however this has since been closed - regardless of project registration date. 

The most current edition of the v4.1 BD+C reference guide has shifted the potential for points from No Cooling Tower option within the District Energy Systems section. here is a snippet:

DISTRICT ENERGY SYSTEMS

"If cooling towers, evaporative condensers, evaporative cooling systems, and other evaporative cooling systems are not used in the district cooling system serving the project, or are used in conjunction with compressor-based cooling equipment to supply no more than 10% of the total cooling energy generated by the District Energy System, then the project automatically qualifies for 2 points under the credit (Core and Shell projects automatically qualify for 3 points) and does not need to provide calculations. Provide a narrative description of how the district cooling system is operated and confirm that there is no evaporative cooling equipment in the district energy system."

This item has bounced around a bit in the last year, so the confusion is understandable. 

Hope this helps!

Please also think about the maximum points you can achieve in the Water category. Getting 3 points for Process Water Use Optimization and 3 Points in Outdoor Water Use Reduction means you can only get 4 points in Indoor water use reduction. As per credit substitution guidance and our quesstion to GBCI.

Per LEED v4.1 BD+C Guide, Credit Substitution Section: "If pursuing three points in either Outdoor Water Use Reduction or Optimize Process Water Use, Core and Shell project teams must mark Indoor Water Use Reduction as attempted in LEED Online to properly distribute points." This guidance is regarding the technological limitations of the LEED Online platform, where a maximum of two points can be awarded each for WEc OWUR and WEc Cooling Tower/Process Water. If the team earns a third point following the v4.1 path for either of those credits, the additional point would be awarded within WEc Indoor water use reduction. Note, that the team is not required to use the v4.1 substitution path for Indoor Water Use Reduction for this workaround method.

Concerning your question on maximum available points, regardless of what combinations of v4/v4.1 credit paths are pursued, the project would still be limited to a maximum of 11 points within the WE credit category. The maximum point threshold for v4.1 Indoow Water Use Reduction credit was intentionally lowered for CS projects to 4 points, to account for the additional points available to CS projects within v4.1 WEc OWUR and WEc Cooling Tower/Process Water.

Regards,Lenka

HI Grace, I am targeting the same path for a Core & Shell building. As long as the baseline system is one of those listed, which would include a cooling tower, and your project has no cooling tower you can target all 3 points for C&S under Optimize Process Water Use, Option 2. This strategy was confirmed by LEEDCoach. For New Construction, the 100% reduction via not having a cooling tower earns 2 points for the credit plus an Exemplary Performance point. We plan on documenting the baseline system by providing screenshots of the ASHRAE section that shows that our building is one of those systems (7, 8, 11, 12 or 13).

Option 2. Optimize Water Use for Cooling is available for New Construction projects. Option 2 allows projects to document a 100% reduction in water use for cooling if at least one of the baseline system(s) designated for the building using ASHRAE 90.1-2016 Appendix G Table G3.1.1 includes a cooling tower or evaporative condenser (systems 7, 8, 11, 12, and 13), and the project team eliminates the need for cooling towers or evaporative condensers in the proposed building design, as stated in the LEED v4.1 BD+C Guide (https://build.usgbc.org/bd+c_guide). This approach would be eligible for 2 points for a New Construction project. Also, please note that the 100% threshold for Option 2 would be eligible for an Exemplary Performance point in the Innovation category. The LEED v4.1 BD+C Guide (https://build.usgbc.org/bd+c_guide) states for Exemplary Performance, "Option 2. Demonstrate a 100% reduction in annual water use compared to a water-cooled chiller system."

Hello @Marelle Dave,
we are in a similar position where we are pursuing WEc3 - Option 2 for a new construction. In our proposed design we have air cooled chillers and baseline system is system 7 with water cooled chillers. We believe we are eligible to target 100% reduction on process water use and we have created a narrative to support this, in your experience was there any other documentation to be submitted?

Hi Kathy, 

I haven't yet submitted that project so don't have any feedback from a GBCI reviewer to share, but I belieive the documentation demonstrating that ASHRAE baseline system and the mechnical plans showing no HVAC process water use should be sufficient documentation. 

Hi Kathy, 

Similar to Marelle, I have not submitted this option in v4.1 either. 

But looking at the v4.1 credit template, Option 2 Optimize Water Use for Cooling requires the following uploads:

1. documentation showing that project Baseline System is designated as systems 7, 8, 11, 12 or 13 under ASHRAE 90.1-2016 Appendix G Table G3.1.1.

2. site or mechanical system plan, energy model or other showing project design. 

3. calculations demonstrating percent reduction in cooling tower water usage for systems where the proposed design uses the latent heat of evaporative cooling of water, or narrative describing the district cooling system operation. 

I think we are overthinking it, and the scenario you describe will allow you to document a 100% reduction in water use for cooling without the need for calculations, rather a simple narrative should suffice.

Odd that this credit template asks for documentation showing the proejct Baseline System (this is listed within the General HVAC tab of the MEPC) or the energy model (that is found in EAp2) or site/mechanical plans (that is found in PI) or calculations demonstrating percent reduction for air cooled chillers (some water for cooling vs no water for cooling = 100% reduction).

Good Luck!

Thank you @Marelle & @Dave. Appreciate your prompt response.